Psychiatrist in Pune , Dr Neville Misquitta (MD Psychiatry). This is a psychiatrists take on Pune occurrences. Mental health issues reflect underlying universal problems that keep some of us from a meaningful life. At Pathfinder Clinic we make the link.

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Saturday, December 17, 2011

Drinking and driving

Alcohol and driving don’t mix. In a flashback to Alex’s drug influenced joyride in A Clockwork Orange, a Pune youth bumped into four people at different points on his late night drive through the city. When chased and caught he was found to be under the influence of alcohol.

In this post we take a look at the effects of alcohol on driving. We have already discussed some of the long term effects that necessitate imposing legal age limits for alcohol consumption in order to mitigate its neurotoxic effects on the developing brain.

30mg% is the legal blood alcohol concentration (BAC) limit for driving. Limits are a safety requirement to counter the adverse effects of alcohol on driving ability. The 30mg% level is often panned as being too low. Most countries have settled at a 50mg% threshold, some at 20mg%, others (considered very liberal) at 80mg%. Lets take a look at the effects on driving at these various blood alcohol concentrations (CDC 2011).

BAC

Effect on driving

20mg%

Visual deficits (problems with tracking of a moving object), Decline in multitasking ability (talking to a passenger while driving)

50mg%

Reduced coordination, difficulty steering, increased reaction time for braking by more than a second (Siliquini 2011)

How long after drinking alcohol is it safe to drive?You need to wait at least as many hours as the ‘chota pegs’ (1oz or 30ml) you consumed.Alcohol is digested by the liver. The liver has a fixed capacity to metabolise about 8gms of alcohol in an hour. This is the amount of alcohol in 30ml of whisky, vodka, rum or gin. The equivalent dose is 250ml of beer or a glass (150ml) of wine. Each of these is considered as a ‘unit’ of alcohol. However, consuming any quantity of alcohol within 6 hours prior to driving is associated with a doubling of the risk for a road traffic accident (Di Bartolomeo 2009). This effect of alcohol is present even at intake of 1-2 units which works out to a BAC of approximately 50mg%.

Blood alcohol levels as low as 20mg% impair driving ability under test conditions in a simulator. At 50mg% the impairments more than double the risk of an accident. The present 30mg% level may be legal but it remains impairing. Better to have a ‘designated driver’ - the person who does not drink for that particular evening. In case you want to we have already studied how to refuse alcohol.